Some participants in HIV prevention trials engage in more risky behaviors after they enroll in a trial, a phenomenon known as "behavioral disinhibition." Such behaviors can compromise the health of the research participant and the scientific value of the prevention trial. Efforts to reduce these behaviors through risk counseling and education are not always successful. The objective of "PREMIS: Preventive Misconception in HIV Prevention Trials" is to understand how risk behavior may be related to participants'false beliefs about the prevention trial and the investigational intervention being tested. In previous work, we have referred to these false beliefs as the "preventive misconception" and have suggested that they could arise from the way the informed consent process takes place. A better understanding of the relationship between the preventive misconception and risk behavior could inform efforts to modify the consent process in prevention trials to reduce the negative effects of increased risk behavior. To achieve our objective, we will pursue 3 specific aims: (1) To refine a conceptual model of preventive misconception. (2) To develop and evaluate a measure of preventive misconception. (3) To explore whether scores on the newly developed measure of preventive misconception are associated with risk behavior among participants enrolled in HIV prevention trials. We will collect data from a total of 280 US participants in trials conducted by the HIV Prevention Trials Network. At the completion of the study, we will have defined and measured the preventive misconception and provided the first clear data on the relationship between the preventive misconception and risk behavior. PUBLIC HEALTH RELEVANCE: HIV prevention trials raise important ethical questions. The proposed research may help investigators and institutional review boards to design and test modifications to the informed consent process to minimize beliefs and behaviors that jeopardize the ethical status of prevention research. Such interventions may help to reduce the risk of HIV transmission for participants in prevention trials and increase the scientific value of these trials.